1. Field of the Invention
The present invention relates to an image input system, etc., and more particularly, to a device which automatically correcting an English document image that is input by using an image input device such as a scanner, etc. to be a properly orientated image, and obtains a properly orientated document image, especially, by detecting as document correction methods a rotation, a rotational angle if the rotation is required, and mirror image flipping, which are intended for correcting an input document image to be properly orientated, from the input document image after the rotation or the mirror image flipping.
2. Description of the Related Art
In recent years, a manual hand-held scanner which is small-sized and easy to carry has been developed and commercialized in addition to a stationary flat-bed scanner. With the hand-held scanner, a user can perform scanning in an arbitrary direction at a high degree of discretion. However, an image may sometimes be read as a rotated image or a mirror image depending on a scanning direction. Therefore, the image must be corrected by being rotated or flipped back to the right-reading image.
With a conventional document image correcting device such as the one disclosed by Japanese Laid-open Patent Publication No. 8-212298, a character image is extracted from a scanned document image. Character recognition is performed in four directions such as in 0-, 90-, 180-, and 270-degree directions. The direction in which the degree of the likelihood (accuracy) of recognition is the highest is determined to be the orientation of the document. If the determined document orientation is not a correct orientation, the document image is corrected to be properly orientated (the orientation in which the image can be properly read as a document) by rotating the image.
Accordingly, with the conventional document image correcting device, character recognition cannot be made for a document image which is obtained by being scanned with a hand-held scanner and is flipped to a mirror image, if the character image which is extracted from the document image is rotated by any of the angles such as 0, 90, 180, and 270 degrees. As a result, its correct orientation cannot be determined, leading to a correction not being possible.